煤岩组合体卸围压能量演化规律及耗散能损伤本构模型研究  

Energy evolution of unloading confining pressure and dissipative energy damage constitutive model of coal-rock combination

作　　者：茹文凯 胡善超[1] 李地元[2] 马金银 张晨曦 罗平框 弓昊 周奥辉 RU Wen-kai;HU Shan-chao;LI Di-yuan;MA Jin-yin;ZHANG Chen-xi;LUO Ping-kuang;GONG Hao;ZHOU Ao-hui(School of Energy and Mining Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;School of Resources and Safety Engineering,Central South University,Changsha,Hunan 410083,China)

机构地区：[1]山东科技大学能源与矿业工程学院,山东青岛266590 [2]中南大学资源与安全工程学院,湖南长沙410083

出　　处：《岩土力学》2023年第12期3448-3458,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.5190040670,No.52274087);山东省自然科学基金(No.ZR2023ME189)。

摘　　要：煤炭资源开采过程中,半煤岩巷掘进和薄煤层回采都不可避免地会使煤岩组合系统发生自由面卸荷。自由面卸荷现象往往伴随着能量的快速积聚与释放,所以探究煤岩组合体试样卸围压条件下的能量演化规律十分必要。为此,针对煤岩组合体试样开展了不同卸荷速率的卸围压试验。结果表明:(1)轴向加载阶段和应力恒定阶段为组合体试样的主要储能阶段,失稳破坏阶段主要以能量的释放和耗散为主;(2)卸荷速率加快会导致试样峰值弹性能降低,0.03 MPa/s时峰值弹性能分别为0.06、0.09、0.12 MPa/s时的1.64、2.70、3.50倍;(3)卸荷速率加快会导致试样峰后耗散能的增加,0.03、0.06、0.09、0.12 MPa/s卸荷速率下,峰后耗散能量分别为峰值弹性能的28.17%、49.53%、69.55%、92.87%;(4)卸荷速率的增大会显著增强煤岩组合体试样的拉伸破坏趋势,导致断裂角增大、拉伸次生裂纹增多和破坏强度增强;(5)建立考虑初始损伤的耗散能本构模型,合理阐释了卸围压条件下煤岩组合体试样损伤演化全过程。该研究成果对于了解卸围压速率对煤岩组合体试样的能量演化特征具有重要意义。In coal mining,the excavation of a coal-rock roadway and a thin coal seam will inevitably cause radial unloading of the coal-rock combination system.The radial unloading phenomenon is often accompanied by the rapid accumulation and release of energy,so it is necessary to investigate the energy evolution law of coal-rock combination specimens under the unloading confining pressure condition.To this end,the unloading confining pressure tests with different unloading rates were carried out for the coal-rock combination specimens.The results show that:(1)The axial loading and constant stress stages are the main energy storage stages of the combination specimens.The failure stage is mainly dominated by the release and dissipation of energy.(2)The acceleration of the unloading rate leads to the decrease of the peak elastic energy of the specimens,and the increment of the elastic energy at 0.03 MPa/s in the constant stress stage is 1.64,2.70 and 3.50 times of that at 0.06 MPa/s,0.09 MPa/s,and 0.12 MPa/s,respectively.(3)The increase of unloading rate will lead to the increase of post-peak dissipation energy of the specimen,and the post-peak dissipation energy is 28.17%,49.53%,69.55%and 92.87%of the peak elastic energy when the unloading rate increases from 0.03 MPa/s to 0.12 MPa/s,respectively.(4)The increase in unloading rate will significantly enhance the tensile failure tendency of coal-rock combination specimens,resulting in an increase in the fracture angle,an increase in the number of tensile secondary cracks,and an enhancement in the breaking strength.(5)A dissipative energy constitutive model considering the initial damage is established to reasonably explain the whole process of damage evolution of coal-rock combination specimens under the unloading confining pressure conditions.The research results are significant for understanding the energy evolution characteristics of coal-rock combination samples with unloading rate.

关 键 词：煤岩组合体 卸围压 能量 损伤 本构方程 

分 类 号：TU452[建筑科学—岩土工程]